Argonne in the marketplace: Ultrananocrystalline diamond

Even as royalty set diamonds into crowns and rings, engineers lusted after the gems for different reasons: diamonds are stronger than any other natural material and are excellent electrical insulators and heat conductors. Today they are widely used in industry and factories. But the diamond supply is limited, and while you can make artificial diamonds in gem form, they have been hard to synthesize in thin films.

A technique invented at Argonne National Laboratory creates thin films of diamond with grains so small they're called ultrananocrystalline diamond (UNCD®) films. The films can be applied to an astounding array of surfaces and uses, ranging from better seals on pumps to heart pump walls so smooth that dangerous blood clots don't form. The grains of diamond in the film are just five nanometers across—about a billion of them would fit inside one red blood cell.

UNCD captures most of the natural properties of diamond. The films are harder than any other diamond film demonstrated today; they are extremely smooth and chemically inert—so they don’t interact with other substances—and they are good electrical conductors when doped with nitrogen or boron. Each film can be precisely tailored.

Advanced Diamond Technologies Inc., in Romeoville, Illinois, formed as a start-up company spun out of Argonne in order to manufacture UNCD products. For example, if you coat mechanical pump seals with UNCD, the film is so smooth that it reduces friction and saves up to 20% of the energy used to run the pump. The coating has also been successfully used to develop atomic force microscope tips and on bearings in industrial mixers.

The U.S. Department of Defense is working with the company to use the films in sensors that would take quick readings to detect chemical and biological threats in water. Diamond, unlike most other materials, can bond with biomolecules like E. coli, Salmonella, Listeria and other pathogens in water to detect their presence. The goal is to miniaturize the detectors so that anyone, including soldiers, police, or public health officers, could carry them.

Finally, because diamond is chemically inert, it doesn't react with biological human tissue or body fluids—and the body doesn't reject the diamond as a foreign material. For this reason, UNCD can be used in implants, including artificial retinas and heart pumps to treat heart failure.